The only solution to this problem I have found is to use a rich text editor instead of a web part zone, but that isn't really the same thing.
Yet another day in SharePoint paradise...
"We have recently uncovered an issue with this Service Pack 1 package that may prevent customers who have Service Pack 1 from deploying future public or cumulative updates. As a precautionary measure, we have deactivated the download page until a new package is published."Yet another day in SharePoint paradise...